The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics cir...The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics circuit. A very clean signal with very low background noise was obtained by applying a transformer between the delay-line and the pre-amplifier in order to match the resistance. Along the anode wire direction a position resolution of less than 0.5 mm was achieved with a ^55Fe-5.9 keV X ray source. The simple structure, large effective area and high position resolution allow the application of a gas chamber of this kind to many purposes.展开更多
The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that wi...The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that will be used for various studies on heavy-ion collisions. A multi-wire drift chamber(MWDC) array is the forward tracking detector of the CEE. In this work, GEANT4 simulations were performed for the MWDC forward tracking array with a focus on the track reconstruction algorithm. Combined with the time of flight information,particle identification is achieved. The residue is about 30 μm, while the tracking efficiency is higher than 90%with the current redundancy. In addition, a prototype of the forward tracking system using three MWDCs was assembled and tested using a high-energy proton beam. The firing efficiency of the detector and the reconstruction accuracy of the prototype were derived. The track residue for the protons at about 400 MeV/c is better than 300 μm, meeting the requirements of the CEE. Suggestions for improving the performance of the forward tracking system are given.展开更多
大容积环境测试舱内温湿度控制系统具有非线性、时变性和耦合性的特点,传统的比例积分微分(Proportion integral differential,PID)控制器参数整定方法不能满足环境测试舱温湿度控制的要求。只有获得PID控制器的最优参数才能实现环境测...大容积环境测试舱内温湿度控制系统具有非线性、时变性和耦合性的特点,传统的比例积分微分(Proportion integral differential,PID)控制器参数整定方法不能满足环境测试舱温湿度控制的要求。只有获得PID控制器的最优参数才能实现环境测试舱温湿度的优化控制。该文提出一种遗传算法(Genetic algorithm,GA)优化PID控制器参数的控制算法—GA-PID。首先通过预估解耦方法对温湿度解耦,然后将目标函数作为控制器的评估值,通过遗传算法的选择、交叉、变异、迭代功能获得PID控制器参数的最优解,以弥补常规PID算法在环境测试舱温湿度控制系统中的不足。通过MATLAB进行了仿真实验,实验结果表明预估解耦可有效地对温湿度进行解耦,提出的GA-PID控制算法可实现快速、准确以及稳定的环境测试舱温湿度控制,具有更好的控制性能。展开更多
目的:探究双腔心脏起搏器植入患者的心肺耐力特点,分析可能影响其心肺耐力的因素,指导双腔心脏起搏器植入患者的心脏康复治疗。方法:回顾性分析了67例双腔心脏起搏器植入患者(起搏器植入组)与匹配的128例一般人群(非起搏器植入组),比较...目的:探究双腔心脏起搏器植入患者的心肺耐力特点,分析可能影响其心肺耐力的因素,指导双腔心脏起搏器植入患者的心脏康复治疗。方法:回顾性分析了67例双腔心脏起搏器植入患者(起搏器植入组)与匹配的128例一般人群(非起搏器植入组),比较两组临床资料、生化指标、超声心动图参数以及心肺运动测试结果,探究双腔心脏起搏器植入患者的心肺耐力特点。对起搏器植入患者进行亚组分析,通过二元Logistic回归模型进行多因素分析,探寻影响双腔心脏起搏器植入患者心肺耐力的因素。结果:起搏器植入组无氧阈心率、峰值心率、峰值心率占预计值百分比明显低于非起搏器植入组(94.16±18.14 vs105.48±16.36bpm,P<0.001;115.07±22.14 vs 130.14±20.93bpm,P<0.001;75.67±13.64%vs 85.18±11.24%,P<0.001),起搏器植入组峰值摄氧量低于非起搏器植入组(16.8±4.14 vs 18.65±3.90ml/kg/min,P<0.05),两组摄氧效率斜率、二氧化碳通气当量斜率均值无显著性差异(P均>0.05)。起搏器植入组进行亚组单因素分析发现年龄、运动习惯、心室起搏比例、植入年限在两组之间具有显著性差异,多因素分析发现心室起搏比例≥40%是起搏器植入患者心肺耐力下降的独立危险因素(P<0.05,OR=0.167)。结论:双腔心脏起搏器植入患者心肺耐力下降,年龄、运动习惯、心室起搏比例、植入年限是影响其心肺耐力的重要因素,其中心室起搏比例≥40%是影响心肺耐力的独立危险因素。展开更多
目的观察具备起搏模式策略和AV间期延长的策略功能的起搏器(Adapta)的远期临床效果。方法 39例患者随机分组,置入具有自动化功能的Adapta起搏器(实验组,n=20)和其它类型双腔起搏器(对照组,n=19)。并分别在置入前及置入后1,2年进行随访...目的观察具备起搏模式策略和AV间期延长的策略功能的起搏器(Adapta)的远期临床效果。方法 39例患者随机分组,置入具有自动化功能的Adapta起搏器(实验组,n=20)和其它类型双腔起搏器(对照组,n=19)。并分别在置入前及置入后1,2年进行随访。随访中观察两组的右室起搏比例、心功能(纽约心功能分级、血脑钠肽)、左房内径(LAD)、左室舒张末内径(LVEDD)、左室射血分数、持续性心房颤动发生率及生活质量等的变化。结果置入双腔起搏器术后1年及2年,与对照组比较,实验组心室起搏比例均明显降低(38.21%±46.01%vs 92.52%±2.70%;36.22%±73.09%vs 91.78%±7.63%,P均<0.05)。置入术后2年,对照组与实验组及与自身术前比较,LAD,LVEDD增大(LAD:43.11±7.08 mm vs 39.01±3.72 mm,40.02±4.70 mm;LVEDD:53.60±6.91 mm vs 47.71±4.79 mm,46.57±3.99 mm,P均<0.05)。其他指标两组无明显差异。结论起搏器自动化功能可以有效降低心室起搏比例、保护心功能。展开更多
基金Major State Basic Research Development Program of China (2007CB815002)NSFC (10775003, 10827505)
文摘The design principle for a multi-wire proportional chamber with a cathode strip and delay-line readout is described. A prototype chamber of a size of 10 cm×10 cm was made together with the readout electronics circuit. A very clean signal with very low background noise was obtained by applying a transformer between the delay-line and the pre-amplifier in order to match the resistance. Along the anode wire direction a position resolution of less than 0.5 mm was achieved with a ^55Fe-5.9 keV X ray source. The simple structure, large effective area and high position resolution allow the application of a gas chamber of this kind to many purposes.
基金supported by the National Basic Research Program of China(973)(No.2015CB856903)the National Science Foundation of China(No.U1332207)
文摘The building of a large-scale external-target experiment, abbreviated as CEE, in the cooling storage ring at the Heavy Ion Research Facility in Lanzhou has been planned. The CEE is a multi-purpose spectrometer that will be used for various studies on heavy-ion collisions. A multi-wire drift chamber(MWDC) array is the forward tracking detector of the CEE. In this work, GEANT4 simulations were performed for the MWDC forward tracking array with a focus on the track reconstruction algorithm. Combined with the time of flight information,particle identification is achieved. The residue is about 30 μm, while the tracking efficiency is higher than 90%with the current redundancy. In addition, a prototype of the forward tracking system using three MWDCs was assembled and tested using a high-energy proton beam. The firing efficiency of the detector and the reconstruction accuracy of the prototype were derived. The track residue for the protons at about 400 MeV/c is better than 300 μm, meeting the requirements of the CEE. Suggestions for improving the performance of the forward tracking system are given.
文摘大容积环境测试舱内温湿度控制系统具有非线性、时变性和耦合性的特点,传统的比例积分微分(Proportion integral differential,PID)控制器参数整定方法不能满足环境测试舱温湿度控制的要求。只有获得PID控制器的最优参数才能实现环境测试舱温湿度的优化控制。该文提出一种遗传算法(Genetic algorithm,GA)优化PID控制器参数的控制算法—GA-PID。首先通过预估解耦方法对温湿度解耦,然后将目标函数作为控制器的评估值,通过遗传算法的选择、交叉、变异、迭代功能获得PID控制器参数的最优解,以弥补常规PID算法在环境测试舱温湿度控制系统中的不足。通过MATLAB进行了仿真实验,实验结果表明预估解耦可有效地对温湿度进行解耦,提出的GA-PID控制算法可实现快速、准确以及稳定的环境测试舱温湿度控制,具有更好的控制性能。
文摘目的:探究双腔心脏起搏器植入患者的心肺耐力特点,分析可能影响其心肺耐力的因素,指导双腔心脏起搏器植入患者的心脏康复治疗。方法:回顾性分析了67例双腔心脏起搏器植入患者(起搏器植入组)与匹配的128例一般人群(非起搏器植入组),比较两组临床资料、生化指标、超声心动图参数以及心肺运动测试结果,探究双腔心脏起搏器植入患者的心肺耐力特点。对起搏器植入患者进行亚组分析,通过二元Logistic回归模型进行多因素分析,探寻影响双腔心脏起搏器植入患者心肺耐力的因素。结果:起搏器植入组无氧阈心率、峰值心率、峰值心率占预计值百分比明显低于非起搏器植入组(94.16±18.14 vs105.48±16.36bpm,P<0.001;115.07±22.14 vs 130.14±20.93bpm,P<0.001;75.67±13.64%vs 85.18±11.24%,P<0.001),起搏器植入组峰值摄氧量低于非起搏器植入组(16.8±4.14 vs 18.65±3.90ml/kg/min,P<0.05),两组摄氧效率斜率、二氧化碳通气当量斜率均值无显著性差异(P均>0.05)。起搏器植入组进行亚组单因素分析发现年龄、运动习惯、心室起搏比例、植入年限在两组之间具有显著性差异,多因素分析发现心室起搏比例≥40%是起搏器植入患者心肺耐力下降的独立危险因素(P<0.05,OR=0.167)。结论:双腔心脏起搏器植入患者心肺耐力下降,年龄、运动习惯、心室起搏比例、植入年限是影响其心肺耐力的重要因素,其中心室起搏比例≥40%是影响心肺耐力的独立危险因素。
文摘目的观察具备起搏模式策略和AV间期延长的策略功能的起搏器(Adapta)的远期临床效果。方法 39例患者随机分组,置入具有自动化功能的Adapta起搏器(实验组,n=20)和其它类型双腔起搏器(对照组,n=19)。并分别在置入前及置入后1,2年进行随访。随访中观察两组的右室起搏比例、心功能(纽约心功能分级、血脑钠肽)、左房内径(LAD)、左室舒张末内径(LVEDD)、左室射血分数、持续性心房颤动发生率及生活质量等的变化。结果置入双腔起搏器术后1年及2年,与对照组比较,实验组心室起搏比例均明显降低(38.21%±46.01%vs 92.52%±2.70%;36.22%±73.09%vs 91.78%±7.63%,P均<0.05)。置入术后2年,对照组与实验组及与自身术前比较,LAD,LVEDD增大(LAD:43.11±7.08 mm vs 39.01±3.72 mm,40.02±4.70 mm;LVEDD:53.60±6.91 mm vs 47.71±4.79 mm,46.57±3.99 mm,P均<0.05)。其他指标两组无明显差异。结论起搏器自动化功能可以有效降低心室起搏比例、保护心功能。
